Such apparatuses have a device for monitoring the status of a safety device for the machine, in particular a safety switch for monitoring the closed status of the safety gate or the like of the safety device. When the safety device is in a closed state, the apparatus can provide an enabling signal for the operation of the machine. When the safety device is in an opened state, the safety switch interrupts one or more circuits, for example, by an electrical contact pair that is actuated by positive locking or by an electronic switching element. The enabling signal is then no longer provided. The associated machine is thereby transferred to a secure operational state, for example, shut down, or a startup of the machine is prevented.
A safety switch is known from EP 0 801 801 A1, in which a mechanically encoded actuator can be inserted in a switch head, upon which a control gear rotates. The control gear actuates an electrical switch by a plunger.
A safety switch, known from DE 197 11 588 A1, has a reading head and an electronically encoded actuator, each of which have a first or second electronic assembly respectively having electrical and/or electronic components. These components can be brought into interaction with one another without an electrical contact, and thereby, control the safety switch.
For safety switches having a mechanically encoded actuator, blocking inserts are known. Blocking inserts are inserted into the switch head of the safety switch and can be secured there against unauthorized removal. When the locking insert is inserted, it is no longer possible to insert the actuator into the switch head, so that the safety switch prevents the machine disposed inside the safety device from starting up, either directly, or by a superordinate control device. Such blocking inserts may be used by machine technicians, for example, so that, when entering the space within the safety device, they can prevent the machine from being made operational when the safety device is closed. For this purpose, the blocking inserts can also be fixed to the switch head by U-locks.
A safety control and a method for controlling an automated system is known from DE 10 2008 060 010 A 1.
An apparatus for monitoring the status of a safety device of a machine is known from DE 10 2008 055 685 A 1.